Gragas q locks up and can't use

About 10 games ago I played gragas jungle, in the middle of the match at about 20 minutes, his q became unable to use. I tried locking it to other keys. Still no success. We ended up losing because I couldn't use this ability. My team thought I was trolling and reported me. I don't even want to play gragas anymore in ranked because It might happen again. Anyone heard of this before?